InformationWeek's Fred Langa details how you can do a total rebuild of Windows XP without losing any data and without having to reinstall software - basically giving you a fresh, nondestructive installation of XP.

I've been asked by readers on more than one occasion if this sort of thing is possible (specifically re-installing Windows but keeping installed software in tact), but I'd never seen it done. This method isn't a reinstallation, exactly, but it repairs any problems in your previous installation of XP (which presumably is the reason you're doing this in the first place) while keeping all of your user accounts, data, and installed programs in tact. Could come in very handy if you've got everything how you like it, but a glitch deep in your Windows bowels is making enough trouble that you're on the verge of a reformat. — Adam Pash